The Myth of the "Cold and Flu Season" - January 19, 2011

Doesn’t it seem strange that there is such a thing as "seasonal" illness? That is, why would sickness-promoting bugs (viruses and bacteria) only come around during the fall and winter months? Well, they don’t of course. This is a MYTH! We are exposed to so-called "bad bugs" all the time, yet most of us avoid sickness. Why is that? The key determining factor in deciding who gets sick and who stays well is NOT the presence of "bad bugs" – it is the state of our IMMUNE FUNCTION. In other words, bugs only flourish in fertile soil (a weak immune system). One of the better studies demonstrating this was done by Cohen et al. in 1991 where they exposed all subjects to the cold virus but only those who were "stressed" developed a cold. 1

Many factors can influence the function of our immune system, with one of the most documented factors being the amount of stressors in our lives. Stimulation of the stress response by such factors as high blood sugar, lack of sleep, a lack of exercise, negative thoughts, or spinal misalignment often sets off the neurobiochemical down-regulation of our immune system. Since the amount of stress in our lives is not necessarily seasonal (though it may be for some) as indicated by the fact that many people still get colds or flus in the summer, what seasonal variable can explain a significant change in our immune function? Vitamin D! 2

Vitamin D is genetically required to stimulate our innate immune system and is essential for the control of insulin sensitivity, blood pressure, inflammation, and blood coagulation, which is why Vitamin D deficiency is a significant causal factor in cancer, heart disease, multiple sclerosis, autism, asthma, and diabetes. 3

So, during the fall and winter months (as well as the rest of the year when we are inside or covered with clothing or sunscreen outside) we simply do not produce enough Vitamin D due to a lack of sun exposure. Thus, we end up being more susceptible to colds, flu, and all infections due to the lack of sufficient Vitamin D and resulting reduced immune function.

Sources

  1. Cohen, S. et al. Psychological stress and susceptibility to the common cold. N. Engl. J Med 1991 Aug 29; 325 (9); 606-612.
  2. Aloia JF, Li-Ng M. Re: epidemic influenza and vitamin D. Epidemiol Infect. 2007 Oct; 135 (7): 1095-6; author reply 1097-8.)
  3. Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer? IntJ Epidemiol. 1980 Sep;9(3):227-31.; Cantorna MT. Vitamin D and its role in immunology: multiple sclerosis, and inflammatory bowel disease. ProgBiophysMol Biol. 2006 Sep;92(1):60-4.; Wang TJ, et al. Vitamin D deficiency and risk of cardiovascular disease. Circulation. 2008 Jan 29;117(4):503-11.